Hibernation/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim is bundled up in a warm coat and scarf. He is walking through a forest with Moby on a winter day. There is snow on the ground. TIM: Man, it's cold. MOBY: Beep! Moby opens the control panel in his chest and takes out a mug of hot cocoa, which he hands to Tim. TIM: Whoa. Thanks. Tim drinks the cocoa and reads from a typed letter. TIM: Dear Tim and Moby, why do some animals hibernate? From, Sunny. In the winter, most animals need to eat more to keep warm. The colder it is, the more energy it takes to maintain their body temperature. And that energy comes from food. An animation shows a bird eating a berry from a tree branch that has only one other berry. TIM: Problem is, food is often harder to find in the winter. Some animals solve this problem by migrating. That means temporarily moving to a warmer climate. A second bird joins the first bird on the tree branch, trying to get the last berry. The first bird stops the second bird from taking the berry. The second bird sees a flock of birds in the sky flying away, and flies off too. TIM: Other animals adapt to the colder weather, changing in some way that lets them survive. They might store up food beforehand… grow thicker fur… or change their eating habits. An image shows a squirrel looking at a map of hidden acorns. The screen splits to show an image of a fox putting on a fluffy fur outfit in front of a mirror. The screen splits again to show an image of a wolf ordering rabbit from a restaurant menu as a waiter takes his order. TIM: And some animals solve the problem by hibernating. MOBY: Beep? TIM: No, hibernation isn't just a deep sleep. It's a state of dormancy, or lowered body activity, that conserves energy. During hibernation, the heart rate goes way down, as low as five beats per minute in some animals! Breathing drops off sharply too. Some hibernating animals can go an entire hour without taking a single breath! All this reduced activity results in a way lower body temperature that's within a few degrees of the outside air. An animation shows a small animal dressed in a nightgown and sleeping cap yawning in a little bed. The animal falls asleep. A call-out bubble shows its heart beating slowly and its lungs breathing slowly. A thermal image of the animal changes from redder to greener to bluer as its body temperature drops. A vertical temperature bar next to the animal starts getting shorter and changes from red to green. TIM: In a few animals, like the artic ground squirrel, the body temperature actually drops below freezing during hibernation! An animation shows the thermal image of the small sleeping animal turning from green to blue. A call-out button of one of the animal's cells shows its metabolic activity getting slower and slower. An animation shows a command center inside of the cell with the operator asleep in his chair. TIM: A colder body temperature leads to a lower metabolism. That's the process of energy creation that happens inside our cells. Cellular activity slows down, allowing the animal to survive on less energy. So, it can make it through the winter with little or no food. MOBY: Beep? TIM: Yeah, they do need some energy. Before hibernating, many animals spend days or months eating as much as they can to build up fat. This extra fat insulates their bodies against the cold. And during hibernation, they use their stored fat for energy. An animation shows a fat possum sitting in a hollowed out log eating copious amounts of fruit. The view pulls back and the scene becomes an image on a monthly calendar for the month of November. The pages of the calendar flip through the months from November to April, showing images of the possum sleeping soundly while getting thinner and thinner each month. On the April image, the possum is awake and much thinner than in November. MOBY: Beep? TIM: Of course, animals have to find a good, protected spot where they can remain undisturbed for long periods of time. Some of them hibernate for months and months, through the entire winter. Others wake up as often as once a week to get rid of waste or to snack. An image shows the hollowed out log where the possum is hibernating. An animation shows the small sleeping animal from earlier getting out of its bed and walking towards the bathroom, scratching its tail. TIM: You may have noticed that the animals we’re showing are kind of small. Most animals that hibernate weigh less than 50 pounds. Rodents, marsupials, fish, snakes, and frogs all include hibernating species. Images show the animals Tim names as compared to a 50 pound weight. MOBY: Beep? TIM: Well, the reason is that smaller animals have a harder time staying warm in cold weather. Because their bodies have more surface area compared to volume. So that's more places for heat to escape. An image shows a mouse standing in a snowy forest, wearing earmuffs and shivering. The screen zooms out to show a moose, wearing sunglasses and reclining on a lawn chair while reading. MOBY: Beep? TIM: Well, bears are a little bit different. Their metabolism drops a lot, but their body temperature doesn't fall that much. They can also wake up easily. This state of half-hibernation is called torpor. An animation shows a bear in torpor. The bear wakes up as a small white rabbit hops by, and then goes right back to sleep. TIM: Oh, and by the way, hibernators don't all live in northern climates. They may not get as cold, but tropical areas have winter, too. An image shows hibernating bats hanging upside down in a cave. The cave's opening shows it is located in a tropical forest. MOBY: Beep? TIM: Well, some hibernating animals detect when it's getting warmer outside. For others, chemical signals in their brain alert them that it's time to emerge. Kind of like an internal clock, saying, "Time to wake up and find some breakfast!" An animation shows the small animal from the beginning of the movie with the nightgown and nightcap asleep in its little bed. A thought bubble with an alarm clock in it appears above the animal's head, and the alarm starts ringing. The animal opens its eyes, gets up, yawns, and stretches. TIM: Scientists are still looking into exactly how this works. Tim's phone buzzes. TIM: Anyway, my external clock is telling me it's time to head home. I'd like to load up on dinner, then get under the covers and hibernate 'til morning. MOBY: Beep? TIM: It's… It's a figure of speech. Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts